Hey, All!!!
I hate to continue to come on here with pleas for help. But I am having a heckuva time trying to get some back brakes on my 2010 280 Gas Gas, & wonder if any of y'all have ever had to beat this deal, & how you did it.
This isn't my first rodeo with bleeding brakes. My KTM's front could be a booger to get air-free at times, but was still pretty easy compared to the rear brake on this Gas Gas.
I recently had the swingarm off the bike, cleaning/greasing/replacing swingarm pivot & linkage bearings & seals. Since the brake line runs through the swingarm, and I thought I needed to remove the swingarm, I disco-ed the rear brake line. Got everything back together. New bearings & seals in the dog bones & linkage, new grease & seals for the swing arm. Have new crush washers on each end of the brake line, and seem to have no leaks.
I backed off the pedal adjustment rod into the master cylinder, to be certain the piston in the m/c could return & uncover that port in the m/c bore.
I've tried loosening the banjo bolt(s) & pushing down on the pedal, in an effort to possibly get any air out of the master cyl. & caliper. I've used a syringe to force fluid through the system from the line for the reservoir back to the bleed nipple, like in Jim Snell's video at
www.trialspartsusa.com . I've tried bleeding with the syringe hooked up to the bleed nipple, and forced fluid backwards up into the reservoir. And I've bled the goofy thing "conventionally", by pumping the brake pedal & holding it, while cracking open the bleed nipple & closing it before allowing the pedal to return back. And I've still got really, crummy brakes in the back. I've gone through a whole quart of DOT 4 brake fluid, almost, and still have funky brakes.
Actually, the pedal feels fairly firm after all this. It just doesn't seem to force the pistons out of the caliper far enough to really clamp down on the rotor. My "benchmark" of how well the back brake is working is by standing on the bike in my barn, balanced, and then do a front wheel hop. I figure if it clamps hard enough for me to hop the front wheel on my concrete floor, as it used to do, it's likely as good as it ever was. Or, if the rear wheel skids on the concrete, instead of rolls, I'd think my brake is OK. Every now & then, it does seem to hold well enough to hop the front wheel, but it taks a lot of pedal pressure. Most times, the wheel "spins" while the brake makes a kind of moaning/squawking sound as I go backwards a few inches. I'm now currently waiting for new brake pads, and will try those. Maybe I got brake fluid all over the old pads? I know this has been one of the messiest deals I've ever had doing this job. The old pads still have about .100", or 2.5 mm of material left; I'd think that would still be in allowable limits.
I still have my fuel tank off, my airbox/rear fender off, & even my muffler off (waiting on O-rings & a new crush gasket for the exhaust) while I work on the bike. One positive about all this is that the bike seems INCREDIBLY easy to balance without all that stuff on, for some reason....
Anyway, sorry for the novel here. I'm hoping that with all this info, someone can maybe think of something else I need to try, or tell me what I've done wrong, or??
Thanks for any advice, cussing, help, or hand grenades you may be able to lend!
Jimmie
